Wow, this brings back memories... For several years while I was at Carnegie Mellon, my friend Chad and I worked at the Fine and Rare Book Room at CMU's Hunt Library. One of the things we had to help catalog and keep in order and good condition and such was indeed CMU's collection of copies of this poem.
Carnegie Mellon houses collection of "'Twas the Night Before Christmas"
AP on NEPA News
"The illustrations are almost always showing a nostalgic view of life in the United States," said Mary Kay Johnsen, the special collections librarian at the Hunt Library. "The illustrations are always showing toys of the parents' generation, not of the toys the kids would be receiving with the book of that year."(via Google News: Carnegie Mellon)